Referring to FIG. 1, a disk drive 100 enclosed in a casing 102 includes a disk 104. The disk drive 100 may be for a HDD (hard disk drive) for example that stores data magnetically. The disk 104 is typically part of a plurality of disks stacked for providing higher data capacity. The disk 104 is spun about a center axis by a spindle motor 106. A transducer 108 is carried and moved by an actuator 110 along the radial direction of the disk 104 that is spinning, for accessing the disk 104 during a read/write operation. Current provided to a voice coil 111 on the actuator along with the magnetic field of magnets 112 cause the actuator 110 to rotate about a pivot 114. Such rotation about the pivot 114 results in movement of the transducer 108 along the radial direction of the disk 104.
For accessing the disk 104 during a read/write operation, the disk 104 is spinning at a high enough speed such that an aerodynamic cushion is developed between the disk 104 and the transducer 108. Thus, the transducer 108 floats over the disk 104 and does not contact the disk 104 during such access. When the disk 104 is not spinning, the aerodynamic cushion is no longer available to float the transducer 108 above the disk 104. For preventing damage to the transducer 108 or the disk 104 from contact between such components, the transducer 108 is stationed at a parking zone when the disk 104 is not spinning. The parking zone may be an inner radial portion 116 of the disk 104 or may be provided as a separate parking zone 118 apart from the disk 104. Such operation and components of the disk drive 100 are known to one of ordinary skill in the art.
Additionally for preventing damage to the transducer 108 or the disk 104 from contact between such components, the position of the transducer 108 is desired to be maintained within the parking zone 116 or 118 even when external force is applied on the disk drive 100. Such an external force is especially likely when the disk drive 100 is part of a portable system that is prone to be bumped or dropped. U.S. Pat. No. 5,365,389 and Japanese Publication No. 1997-231695 disclose stop limits that use magnets for latching the actuator to a predetermined position. U.S. Pat. No. 5,363,261 discloses an actuator latch that also uses magnets for keeping the transducer at a parking zone. However, relying on magnetic force is disadvantageous because an external force that is greater than such magnetic force could dislodge the transducer 108 from the parking zone 118 and onto the disk 104.
FIGS. 2 and 3 illustrate a mechanical actuator latch 120 for a disk drive as disclosed in U.S. Pat. No. 6,529,349. Elements having the same reference number in FIGS. 1, 2, and 3 refer to elements having similar structure and function. Such an actuator latch 120 includes a hook 122 and an end 124 that pivot about a center 126 of the latch 120. In addition, a first latch portion 132 and a second latch portion 134 are formed at the distal end of the actuator 110.
Referring to FIGS. 1, 2, and 3, when an external force is applied on the disk drive 100, the actuator 110 rotates about the pivot 114 either in the clockwise or counter clockwise direction. Referring to FIG. 2, when the actuator 110 rotates in the counter clockwise direction, the first latch portion 132 of the actuator 110 becomes engaged with the hook 122 of the latch 120 to stop further counter clockwise rotation of the actuator 110. Referring to FIG. 3, when the actuator 110 rotates in the clockwise direction, the second latch portion 134 of the actuator 110 becomes engaged with the end 124 of the latch 120 to stop further clockwise rotation of the actuator 110. In this manner, the position of the transducer 108 is maintained to be within the parking zone 118 in FIGS. 2 and 3.
FIGS. 4 and 5 illustrate another mechanical actuator latch 140 for a disk drive as disclosed as prior art in U.S. Pat. No. 6,529,349. Elements having the same reference number in FIGS. 1, 2, 3, 4, and 5 refer to elements having similar structure and function. The latch 140 includes a hook 142 and rotates about a latch pivot 144. In addition, a notch 146 is formed at the distal end of the actuator 110. Furthermore, a crash stop 148 is formed in the disk drive.
Referring to FIG. 4, when the actuator 110 rotates in the counter clockwise direction, the notch 146 of the actuator 110 becomes engaged with the hook 142 of the latch 140 to stop further counter clockwise rotation of the actuator 10. Referring to FIG. 5, when the actuator 110 rotates in the clockwise direction, the actuator 110 contacts the crash stop 148 which forces the actuator to rotate in the counter clockwise direction such that the notch 146 of the actuator 110 becomes engaged with the hook 142 of the latch 140 as illustrated in FIG. 4. In this manner, the position of the transducer 108 is maintained to be within the parking zone 118 in FIGS. 4 and 5.
A disadvantage of such mechanical latches 120 and 140 of the prior art is that a relatively large impact force may be absorbed by the actuator 110 from contact with one of the latches 120 and 140. Thus, when an external force is applied on the disk drive 100, the latch 120 or 140 contacts the actuator 110 that absorbs such impact force. Structural stress from such force absorption disadvantageously results in noise at the transducer 108 and in mechanical damage to the actuator 110 and transducer 108 over time.
Thus, an actuator latch is desired for maintaining the position of the transducer at a parking zone with a minimized amount of force absorbed by the actuator.